Norman f



(No Model.)

N. F. RUTHERFORD.

ELECTRIC ARC LAMP.

No. 477,273. Patenteg June 2}, 1892.

WITNESSES: lA/VE/VTOR g k W 2212722600 1'? Mkerflrd UNITED STATES PATENTOFFICE.

NORMAN F. RUTHERFORD, OF BATHURST, NElV SOUTH \VALES.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 477,273, dated June 21,1892.

Application filed August 13, 1891. Serial No. 402,506. (No model.)

To all whom it may concern.-

Be it known that I, NORMAN F. RUTHER- FORD, a subject of the Queen ofEngland, residing in Bathurst, New South WVales, have invented certainnew and useful Improvements in Are Lamps, of which the following is aspecification.

My invention relates to electriearc lamps, and has for its object theproduction of a simple mechanism for accomplishing the striking of thearc and the maintaining of the same.

The invention consists of two crossed levers pivoted at their point ofintersection. One lever carries or has attached to it on each side ofits pivot a solenoid-magnet in the main circuit and the other lever hastwo similar magnets included in a sh unt-circuit to the arc. The coresof each set of magnets are carried by the opposite leversthat is to say,the cores of the shunt-magnets are attached to the lever carrying themain solenoids, and the cores of the main solenoid are attached to thelever carrying the shunt-solenoids. The carbon electrodes are preferablyinthe form of disks rotatable on the bearings and carried on the ends ofthe two levers.

In the accompanying drawings, Figure l representsin a semi-conventionalmanner my improved lamp mechanism, and Fig. 2 is a modification of thesame.

Referring to the drawings by letter, a and I) represent two crossedlevers pivoted at their intersection upon a stud c. To the lever a andupon each side of its pivot is attached a solenoid-magnet a at. Thesesolenoids are shaped on the are of a circle having for its center thepivot 0. They are attached to opposite sides of the lever, as shown. Thelever b has attached to it in a similar manner and at the same distancesfrom the center two solenoid-magnets b b. The cores of the solenoids a aare curved pieces of soft iron a a attached, respectively, to the leverb at points directly back of the solenoid which it carries and extendingin the opposite direction. The cores of the solenoids I) Z) are curvedpieces of metal Z) 17 somewhat shorter than the pieces a a and areattached to the levers a a at points immediately behind each of thesolenoids which it carries. It will be seen that from this magneticsystem when the solenoids a a are energized they will have the tendencyto separate the adjacent ends of the levers a and Z), and when thesolenoids Z) b are energized they will have the tendency to bring theadjacent ends of the levers together.

D D represent two carbon disks mounted, respectively, on the lower endsof the levers a and I). They occupy planes at right angles to theirrespective levers and with their perimeters in contact, or nearly so.

D represents clock-work supported by the levers and arranged to rotatethe disks D.

The circuits of the lamp are as follows: from positive binding-post bywire 1 through the main solenoidsct a, thenceto one of the carbons D,crossing the arc-space to the other carbon D, and finally to thenegative bindingpost by wire 2. The shunt-circuit 3 extends from thepositive binding-post through theshunt-magnetsb b, and thence to thenegative binding-post.

The operation is as follows: WVhen no current is flowing through thelamp, the weight of the mechanism holds the edges of the carbons incontact. When the current is turned on, the main magnets a to becomestrongly energized, and the pull which they exert on their cores a aseparates the adjacent ends of the levers and establishes the arebetween the carbons D D. \Vhen the arc becomes too long, the resistancethus caused forces the current to flow through the higlrresistanceshunt-magnets I) I), causing them to attract their armatures b b anddraw the adjacent ends of the levers together, thus shortening the arcand making it again normal.

I have described the carbons as made in the form of disks; but when soformed means must be provided for rotating them in order to entirelyconsume them. I therefore mount upon each lever a frame carrying aclock-work D, which engages with the pinion d on a sleeve carrying thecarbon disk. This clock-work may be made to rotate the disk as slowly asdesired.

In Fig. 2 is shown a modification, in which one of the levers carriesthe solenoids, both main and shunt, and the other carries the armatures. The lovers are bent to form one turn of a spiral. The solenoidsand armaturcs are on the ends of the respective lovers. The two arms KK, carrying the carbons,

which in this instance are pencils, are pivoted, respectively, to oneend of each of the levers at the points 70 7c and pass through openingsor rings 70 formed in the other ends of said levers. M represents themain magnet, and N the shunt-magnet. WVhen the current is turned on, Mdraws its armature and the earbons are separated, thus establishing theare. When the shunt-magnet acts, it draws carbons together. It will beobserved that the two magnets act differentially, and that the movementof the carbons is the result of a movement of the two pairs of ends ofthe levers in opposite directions-that is to say, the point 70 movesinward, while the point k moves outward. The movement of the carbon is,therefore, greater than that of either of the armatures.

I claim- 1. The combination, with a pair of levers pivoted at theirintersection, each carrying a carbon electrode, of two pairs ofsolenoids, one in the main circuit of the lamp and the other in theshunt-circuit of the lamp, one of the levers carrying the main magnetsand the cores of the shunt-magnets and the other carrying theshunt-magnets and the cores of the main magnets, substantially asdescribed.

2. In an arc lamp, a pair of levers pivoted at their intersection andcarrying, respectively, the carbon electrodes, in combination with mainand shunt solenoids and the cores thereof, the said magnets and coresbeing carried by the levers, and devices carried by the levers forfeeding the carbon electrodes.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

NORMAN F. RUTHERFORD. lVitnesses:

FRANK S. OBER, WM. A. ROSENBAUM.

